Flooring systems in buildings—such as homes, apartments, and offices—provide a floor surface for an inhabitable space and facilitate the transfer of loads from an inhabitable space to the rest of the building and/or building foundation. In these flooring systems, an underfloor support structure is often included to support the floor surface. There are a wide variety of underfloor support structure designs.
A simple type of underfloor support structure is a single, solid material such as packed dirt or a concrete slab. These types of support structures may be a part of the building's foundation and provide many desirable elements in the field of building construction.
Over time, more complex underfloor support structure designs were developed, which provide benefits not present in the single, solid material type. Some such designs include the use of truss systems, which increase the potential to have weight savings in the underfloor support structure, provide open space within the underfloor support structure, and facilitate the spanning of gaps beneath the underfloor support structure. The ability to span gaps beneath an underfloor support system enables construction of buildings with multiple stories. Saving weight provides a host of benefits, including saving costs, reducing the load on the building's foundation, allowing additional stories to be supported by a foundation, and/or increased ratings for static and dynamic loading in inhabitable spaces. Open space within the underfloor support structure includes its own benefits, such as insulating between the floor and whatever is below the subfloor; placement of utility systems such as plumbing, ducting, and wiring; and/or providing underfloor storage.
Accessible storage is often desirable for those using inhabitable space. While underfloor storage is possible, accessing it is generally cumbersome and preference often seems to be given to storage and storage systems which are above the floor. This can result in underuse of open spaces within underfloor support structures.